youker-assistant: Improper Limitation of a Pathname to a Restricted Directory
CVE-2023-3098 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in youker-assistant from KylinSoft, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.68% chance of exploitation within 30 days, higher than 53% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of youker-assistant you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| KylinSoft | youker-assistant | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 4.4 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 2.0 | 3.2 | Low | CNA (vuldb.com) |
Official description
A vulnerability classified as critical has been found in KylinSoft youker-assistant on KylinOS. Affected is the function restore_all_sound_file. The manipulation leads to path traversal: '../filedir'. Attacking locally is a requirement. The exploit has been disclosed to the public and may be used. Upgrading to version 3.0.2-0kylin6k70-23 is able to address this issue. It is recommended to upgrade the affected component. The identifier of this vulnerability is VDB-230688. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- vuldb.com/?ctiid.230688Permissions Required, Third Party Advisory
- vuldb.com/?id.230688Third Party Advisory
Technical write-ups (may include proof of concept)
- github.com/i900008/vulndb/blob/main/kylinos_vul3.mdExploit, Third Party Advisory
Other vulnerabilities in youker-assistant
- 7.1 High severity
- 7.8 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
- 10.0 Critical severity
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